P40345 Image Large

With the 331 piston (right) next to a Coast High Performance Track Dominator racing 347 piston, notice how the 347’s wrist pin is located way up into the oil-ring lands. This allows the use of a long, 5.400-inch rod for improved rod-length-to-stroke ratio. The positioning does cause some oil use, a non-critical factor on a racing engine. But on Coast’s Street Fighter 347, a shorter 5.315-inch rod is used, so the 347 displacement is achieved without the wrist pin going into the piston’s oil-ring area, a better situation for a street engine.